Remove unused https dependency from the proxy server

[danielvanza]

Description

• Remove the unused https npm dependency from graph-explorer-proxy-server; the imports resolve to Node's built-in https core module, which shadows any same-named package.
• Refresh pnpm-lock.yaml, dropping the dead importer, package, and snapshot entries.

Validation

• pnpm install --frozen-lockfile — lockfile consistent.
• rg -n "https@" pnpm-lock.yaml — no https@1.0.0 entries remain.
• pnpm checks — passed.
• pnpm test — passed (222 files, 2705 tests).
• PROXY_SERVER_HTTPS_CONNECTION=false PROXY_SERVER_HTTP_PORT=9250 pnpm build && pnpm start, then curl -sS http://localhost:9250/status — returned OK (HTTP 200); log line Proxy server located at http://localhost:9250.

Related Issues

• Fixes Remove unused https npm dependency from the proxy server #2196

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have verified pnpm checks passes with no errors.
• I have verified pnpm test passes with no failures.
• I have covered new added functionality with unit tests if necessary.
• I have updated documentation if necessary.

[danielvanza]

Looks like the CI runs are stuck on "awaiting approval" since this is my first PR here. If a maintainer could approve them and take a look when there's time, that would be much appreciated. It's just the unused https dependency coming out of the proxy package, so the diff is small.